Storage apparatuses that use a plurality of memory devices to store large amounts of data handled by computer systems are widely used. A typical storage apparatus includes one or more disk devices, and a control apparatus that controls the writing and reading of data on the disk devices.
As an example of a method to improve the reliability of data storage of such a storage apparatus, a method is known in which a redundant configuration is established to manage data among multiple disk devices, and when an error occurs in one disk device, data is restored by referring to another disk device.
Japanese Laid-open Patent No. 2009-110303 discloses a related technique.
A technique is known that periodically stops mirror processing on a temporary basis and backs up data stored in disk devices at that time.
For example, a technique is known in which an asynchronous state is established at a certain time for an operation volume and a replica volume synchronized with the operation volume, and the replica volume is backed up to a tape device while the operation volume is still operating.